In this Core Facility, we will be responsible for all genotyping for the Center. The Core will function as follows. All subjects seen in components I and IV will be asked for a cell sample to be collected by a simple noninvasive mouthwashing procedure. Samples from approximately 10,000 individuals over the 5 year period will be collected by this Core, the DNA extracted, and stored by ID number. The core will not have access to the identity of any subject. After appropriate subjects are identified by the ascertainment groups, the DNAs to be subjected to genotyping will be retrieved from the freezer, and typed using a semiautomated procedure. For genome-wide typing, approximately 200 markers per subject will be typed to produce an average 20cM resolution map. In addition, zgosity testing and in later years in the program, regional typing at QTLs will be performed on a larger number of subjects. The core will have contacts with the Components in three ways. First samples will be physically provided to the Core from the individual Components requiring DNA banking and future genotyping. The components will subsequently contact the Core and request specific typing (either whole genome scanning, or specific marker testing) to be performed. Finally, the typing data will be made available through direct query of the database from the Components carrying out the analysis.